Epistemological Problems of Testimony

Given that speakers of a language sometimes assert falsehoods and
fail to be sincere, under what conditions, if any, is someone’s
word alone sufficient to justify the beliefs a hearer acquires from
those assertions? Of course, besides the word of the speaker, hearers
also causally depend on believing testimony on other fundamental
sources of knowledge like perception, memory, learning, and inference.
Can the reliability of testimony be justified by appeal to these
sources? This question represents the dominant epistemological problem
of testimony—is testimony an autonomous source of epistemic
authority? Reductionists answer negatively. They are opposed
by anti-reductionists who hold, characteristically on a
priori grounds, that testimony is a source of warrant in itself,
not reducible to warrant derived from these other sources, even if
empirically dependent on them.

The primary speech-act of testimony is a speaker’s saying,
telling, or asserting something (Searle 1969). Assertion puts forth a
proposition that the speaker represents as true (see the entry on
assertion, on norms of assertion, Rescorla 2009):

The utterance of a sentence serves not only to express a thought,
and to refer to a truth-value, but also to assert something, namely
that the thought expressed is true, or that the truth-value referred to
is truth. (Dummett 1981, 298)

In assertion, the speaker extends an invitation to the hearer
(to understand him) e.g., Thomson (1990). To use Kant’s example:
If I start to pack my suitcase in front of you, but I have no plan to
leave then I intentionally deceive you by giving you evidence that I
plan to leave. But I do not invite you to notice or to understand what
I am doing. By contrast, if I said to you either “I am leaving
town” (a lie) or “Don’t worry if you do not find me
here tomorrow” (an intentionally misleading assertion), I do
invite you to understand and believe me. Thereby, I assume
responsibility for the truth and veracity of my assertion, though
arguably less so for the implicature that “I am leaving
town,” see Adler (1997).

Discussion is restricted to cases in which the speaker’s
utterance is meant literally, rather than rhetorically, playfully,
figuratively, fictionally, or ironically. These restrictions are
imposed for brevity, though the discussion is oriented to the primacy
of literal usage and informativeness (see, e.g., Bach and Harnish
1979; McDowell 1980). The primacy of the aim of informativeness
explains why the untruths of tact and related forms of social
politeness should be set aside. The norm of truthfulness is relaxed.
The relaxation is, presumably, a product of tacit consent and
coordination for purposes of sociability and social harmony. Vagueness
and ‘loose talk’ e.g., “The meeting is around 3
pm” are pervasive and essential for at least economy and ease of
comprehension, but they are not treated separately (Bach 2001).

Since we are in great need of information from others, we will not be
so demanding that in order to avoid error, we refuse to take any risks
of misinformation to gain valuable truths. Gelfert (2006) presents Kant
as arguing that we have a presumptive (imperfect) duty not to distrust
others and a duty of fidelity to trust the word of others because a
stance of incredulity is an active suspicion of others and imposes a
higher standard than is socially, conversationally, or epistemically
appropriate.

An epistemological problem enters, however, if our ground for coming
to these beliefs is only the speaker’s word, since that seems a very
weak basis. What reason, if any, is there for a hearer to just take
the speaker’s word, given that the speaker is capable of lies,
deception, error, and poor, ambiguous, or misleading expression? For
the hearer to trust the speaker’s word is for the hearer to
ascribe authority to the speaker. Within the limits of
presumed competence, the hearer ascribes to the speaker justification
or warrant or knowledge for what she asserts. The hearer takes the
speaker to be in a better position to settle the matter easily and
transmit the relevant information, and so seeks the speaker’s
testimony (Gibbard 1990; Brandom 1994; Faulkner 2007; Keren
2007). Does the hearer have good reason to ascribe that authority? In
what follows, this is referred to as the Vulnerability
Problem.

In order to focus on just the Vulnerability Problem, it helps to
identify a class of core cases that isolates our
dependence on the word of the speaker and whatever epistemic resources
are available in ordinary conversational contexts. The following
conditions help to delineate the class of core cases:

The speaker’s testimony is a single sentence. This
eliminates any justification an assertion might receive by being part
of a group of cohering, mutually-supportive assertions.

There is a single speaker. This eliminates the justification the
testimony might receive by corroboration from other speakers.

The context is one where the norm of truthfulness holds and the
purpose is primarily to inform.

The testimony sustains the corresponding belief in the hearer.
This rules out cases such as acquiring the belief that Joan is in
Arkansas because Mary says so. But then you subsequently receive a card
from Joan postmarked in Arkansas. The card enormously diminishes your
epistemic dependence on Mary’s testimony.

The speaker is assumed not to have any special “expert
knowledge” on the topic of their assertion. The topic of expert
knowledge in relation to testimony is prominently discussed within
scientific or legal settings. (See Kitcher 1993; Walton 1997; Brewer
1998; Golanski 2001; W. Jones 2002. For a survey of research on eyewitness
testimony in the law, see Wells and Olsen 2003. We also set aside
testimony whose content is independently problematic for the ascription
of expertise e.g., moral testimony, Nickel 2001; Hopkins 2007; Driver
2006.)

The speaker is not acting under professional or institutional
demands for accurate testimony. This is necessary to focus on the
justification for accepting testimony that derives only from the norms
of the conversational practice.

Finally, the hearer has no special knowledge about the speaker.
For the purposes of the present discussion the ideal speaker should be
a stranger to the hearer, since personal knowledge of a
speaker will affect a hearer’s justification for accepting the
speaker’s testimony.

One might think that a typical core case like asking local
directions from a stranger satisfies this condition. However, the
hearer is likely to quickly recognize whether the speaker is native to
the area, among other easily or effortlessly known matters.

When the above conditions are met, if only approximately, the settings
will be the proper ones for investigating the Vulnerability Problem.
These are ordinary contexts where the norm of truthfulness holds, the
purpose is primarily to inform, the hearer’s information about
the speaker is minimal and there is little or no motivation to deceive
e.g., the time, the weather, driving directions, the location of
notable places, prominent historical facts, sports scores, the
whereabouts of acquaintances, explaining why you are going to the
shopping mall. In these core cases, hearers generally have no
special reason to doubt the speaker’s word, as they would if the
speaker’s assertion is controversial or self-serving.

Three features of our conversational practice indicate the wide scope
of the Vulnerability Problem. The first is our far-reaching
dependence on testimony—a vast number of our beliefs arise
through it and the inferences it justifies (Price 1969; Sosa 1994;
Schmitt 1994a; Insole 2000; in the history of science, Shapin 1994).
After all, our knowledge about how babies are born, how the blood
circulates, the geography of the world, etc. are not acquired by
observation and direct experience (Coady 1992, 82; see also Stevenson
1993; Sosa 1994). Hume correctly noted that “there is
no species of reasoning more common, more useful, and even necessary to
human life, than that which is derived from the testimony of men, and
the reports of eyewitnesses and spectators” (1977 [1748], 74).

A second feature of our conversational practice is that in core
cases hearers normally accept the assertions of speakers. A
difficulty for securing behavioral evidence for this empirical claim is
that a hearer’s noticeable response to the speaker may appear as
acceptance, while in the privacy of the hearer’s mind there is
no unqualified acceptance. However, if this dodge became frequent
enough, it would come to be known. We would noticeably diminish our
trust in the testimonial practice. Assuming then that we do typically
or, more strongly, uniformly accept ordinary informative
testimony, the practice is robust. If speakers were to
epistemically qualify their assertions (e.g., with variants of
“I’m pretty sure that p”), they would risk
less blame if mistaken, yet their assertions would still display
responsiveness to the hearer’s informational interest.

The third feature that attests to the wide scope of the Vulnerability
Problem is the typical infeasibility for hearers to
seriously check or confirm either the speaker’s reliability or
sincerity within the normal constraints of testimonial transmission
and exchange.

In responding to the Vulnerability Problem, the goal is to show that
even given the infeasibility of checking on the speaker, there is much
evidence available to us of the trustworthiness of the testimonial
setting and of the credibility of what is asserted in the core cases
and well beyond. For example, a hearer can easily detect the
speaker’s competence and sincerity with various prospects of
success (e.g., the speaker answers with hesitancy). But the
background evidence to be set out is more general, applying
to most ordinary conversational settings and available with competence
in the practice (Adler 1994, 2002; Faulkner 2000, 2002; Siegel
2005):

1. The predominance of truthful testimony.

Testimony
overwhelmingly transmits truth (non-accidentally). Since actions often
ensue from testimony, we are positioned to notice failure and we would
be responsive to it. So, it is plausible to conclude that where
testimony thrives, it is by-and-large reliable.

However, it has been observed that false testimony is frequent and
unsurprising (Fricker 1994; McDowell 1994). But the significance of
this observation is subject to exaggeration. We expect correct
testimony, and so it is hardly noticed. We are much more attentive to,
and recall much better, erroneous testimony. An illusion arises if the
estimation of the frequency of erroneous testimony is due to
comparisons mainly with cases that one recalls. But the relevant
reference class is the actual totality of testimony.

2.Truthfulness as the norm.

Truthfulness is a
presupposition of the practice of linguistic communication (Lewis
1969, 1975/1983; Schiffer 1972). Truthfulness governs conversational
exchange, allowing assertion to serve its function. Defection from it
can only come in small doses, since otherwise it would undermine the
trust that the defector (‘free rider’) requires. Lying and
deceiving (evasion, misleading) are typically much more troublesome
and riskier than simple honesty, which is reasonably presumed in
myriad everyday social interactions (Fallis 2010, discussion forward
is mainly under the assumption that speakers are sincere; Williams
2002).

Given general conformity to truthfulness and accuracy, the testimonial
practice promises great overall epistemic benefits, which is so obvious
to participants as to go unremarked.

3. Reputation and Sanctions.

The expectation of
truthfulness is sufficiently strong that those who are the victims of
false testimony, whether through error or deception, are likely to
become less trusting. But the scope of that loss of trust will be
extremely narrowly circumscribed, partly because we lack other means
than testimony to acquire the information we seek. In small
communities and institutional settings, though far less so in large
communities where anonymity can be maintained, sanctions and
reputation are a forceful constraint. “Gossip” columnists
probably would not keep their jobs if the readily verified portions of
their factual reports were not largely accurate (see Coady 2006; also
Pullum 1989 on rumors).

Although the Vulnerability Problem has been most provocatively pressed
about science, the constraint of reputation is particularly forceful in
it. Additionally, there are the related constraints of replication,
publicity, and peer review (Shatz 2004). Consequently, despite the
intense competitive nature of science, major defections are unusual.
One overview concludes

No reliable data exist on the incidence of scientific misconduct,
but it is likely that the serious form of it—fabrication and
falsification of data—is rare. (Kevles 1996, 109; however, see Judson
2004 and Freeman 2010)

4. Impersonal knowledge of our informants.

For their
beliefs, informants mainly depend upon reliable sources such as
perception, memory, reasoning, and testimony. Standard moral
development, upbringing, and education aim to instill fundamental
values, honesty and concern for others, in particular. These values
are easily learned because of the obvious advantage and mutual benefit
of receiving accurate information. We learn of types of speakers who
will be more or less trustworthy, depending on circumstances, as well
as topics on which strangers are likely to be more or less
competent.

5. Motivation, Social-Moral Bonds, Cooperation.

It is only very
occasionally that lying is well motivated. In the absence of that
motivation, Burge observes that: “Lying for the fun of it is a form of
craziness” (1993, 474). In general, only occasionally do
speakers stand to gain by transmitting false or unwarranted
testimony.

In conversational exchange, a moral and social bond is generated
between speaker and hearer, even when strangers. The speaker
appropriately feels some duty to answer the hearer’s inquiry, if
she can, or to deny knowing, apologetically, (“Sorry, I
don’t know”) if she cannot. The speaker, though, is promised
no informational compensation in typical exchanges. The only immediate
compensation promised is the hearer’s gratitude.

Speculation on the evolution of communication, however, is that the
practice arose from benefits to the speaker in manipulating
the beliefs of the hearer, since much of the information a speaker has
would be highly valuable, e.g., location of a scarce food source
(Sperber 2001). Still, in cases where there is incentive to defect,
the evident benefits of cooperation suggest a repeated Prisoner’s
Dilemma, where the strategy of tit-for-tat—cooperate to
start, and then mimic the other player—scores better overall in
simulated environments than other strategies. (On tit-for-tat, Axelrod
1984. See also Blais 1987, 1990; Woods 1989; Parikh 2001.) Additional
to its overt features of cooperativeness, tit-for-tat seeks to be
recognized (‘overt’) and it is not a ‘sucker’
as it will retaliate. Yet, tit-for-tat does not hold a grudge. After
punishing a defector by defecting, tit-for-tat resumes cooperation.
Trustworthiness is then likely to emerge from repeated Prisoner’s
Dilemma-like settings, since fixed, recognizable dispositions attract
others because it is a commitment not to be swayed case-by-case
(Gauthier 1986; McClennen 1990).

Speakers’ assertions are expected to be cooperative
contributions in accord with Gricean maxims—to be
truthful, relevant, informative, and well mannered (economical) to the
hearer in conveying a communicative intention (Grice 1989; Neale
1992; the entry on
implicature;
see further on communicative
intentions Strawson 1971 and Schiffer 1972). The Gricean maxims aid us
in explaining why there is a difference between what is said and the
meaning conveyed by the saying of it. Normally, no one would assert
“I know there is an earth.” But that is because it
would be uninformative to assert, not because it is not true. Grice
plausibly claimed that the conversational practice should be thought of
“as something that it is reasonable for us to follow, that we
should not abandon…” (Grandy and Warner 1989, 29).

6. Prior Plausibility.

To be accepted, the content of testimony must
meet a minimal standard of prior plausibility. Given the bulk
of well founded (obvious) beliefs that hearers bring to the testimonial
setting, they are equipped with a powerful filtering device that
automatically sorts assertions to challenge or, for the starkly
implausible, dismiss e.g., “There was a snowstorm in Miami Beach,
last July.”

Since speakers obviously know of this filtering device (as they are
regularly hearers), it will be pointless for them to assert what
manifestly lacks plausibility. Consequently, the simple assertions we
mainly hear are heavily pre-selected, which lends credibility to the
claim that our response to ordinary testimony is typically acceptance.
Prior plausibility plays a crucial role in the corroboration of
testimony—the conditions under which agreement of independent
witnesses raises the probability conferred on what each one testifies
to individually. A theorem on corroboration is proven by Cohen (1977,
1982) and it is critically discussed by Olsson (2002) and Bovens,
et al. (2002). However, as noted earlier, this work is not discussed
because the raising of probability is not through the speaker’s
word alone.

To review: Condition 1 is that testimony is predominantly successful
in fulfilling its claim to truth. Conditions 2–6 explain why
such success should not be surprising. The conversational or
testimonial practice is robustly maintained despite wide variation in
circumstances and vulnerability to misunderstandings, as well as to
speakers’ hasty or ill informed judgments and their ability to lie,
deceive, and mislead. Conditions 2–6 can serve as evidence or
epistemic reasons because they are incorporated into our corpus of
belief and shape our testimonial practices—specifically, our
ease of acceptance or not.

Given the forceful background evidence that we share in acquiring the
practice, the Vulnerability Problem weakens. Our typical acceptance of
testimony does not rest only on the word of a speaker alone, who we
cannot check on and who is capable of unreliability and insincerity.
Our background evidence is much more extensive and solid.

The restriction to core cases is to ensure that no further evidence is
available to the hearer than is found in typical testimonial settings.
Our background evidence (1–6 above) meets this condition. The
restriction to core cases, however, is a restriction imposed to
address the Vulnerability Problem. Now that we have addressed it, the
restriction is lifted (for concerns about the restriction, see Greco
2012). The obvious advantage is to comprehend more of the
epistemological problems of testimony. In numerous cases well beyond
the core, we are as willing to accept testimony as for the core cases:
“The Giants should have gone for the first-down, rather than
punt”; “DNA is a double helix”; “Marcia is sad
because Tom is on the road so much” (Weiner 2003).

Still, in lifting the restriction, the danger it sought to avoid
returns. When we inquire as to the justification or warrant for
accepting testimony, we need to avoid importing evidence or
information that goes beyond what is commonly available.

Epistemological problems related to the Vulnerability Problem can be
clarified and sub-divided by reference to a putative default rule
for testimony (DR) (on default rules, see Bach 1984).
The rule is an explicitly normative analogue to the fact that hearers
do typically accept speakers’ testimony:

If the speaker S asserts that p to the hearer H, then,
under normal conditions, it is correct for H to
accept (believe) S’s assertion, unless H
has special reasons to object.

The use of “correct” in the DR refers to norms
that are not committed to the prescriptive readings of
“ought” or “should” (Shah and Velleman 2005).
What is correct for the assertional practice need not be what is
prescribed for the individual hearer, who might be better off without
the belief. Nevertheless, a natural corollary of the DR
is that the hearer ought to accept the speaker’s word.
But would such an ought be epistemic and prescriptive? If so,
would it be in conflict with the thesis that believing is non-voluntary
(Williams 1973)?

“Accept” is short for “acceptance as true,”
which issues in full or unqualified belief (on accepting for a
purpose, Stalnaker 1984; Cohen 1992). One argument for unqualified
belief as the right aim of hearers is the advantage for cognitive
memory—the difficulties, specifically, of storing, accessing, working
with, and updating qualified beliefs, given acquisition of new
information (Harman 1986; Gilbert 1991, 1993 presents evidence that
believing is psychologically prior to evaluation).

Other versions introduce minor variation on the “normal
conditions” or “unless” clause, which does not bear
on the main issues. However, without restrictions on what counts as a
‘special reason’ or what satisfies the ‘unless’
clause, independent of conditions on acceptance, the DR is
threatened with vacuity (see Sutton 2007).

Asking for simple directions provides a handy illustration of the
DR: If a stranger (speaker) tells you to turn right at the
next corner in answer to your request to find a gasoline station, you
are justified in accepting the assertion without being told you how
the speaker knows it. Unlike argument, where a speaker explicitly
presents reasons to back the assertion, in normal testimony the
speaker does not. Strangers are not expected to tell you why they are
in a position to know that their directions are correct. (Some
languages, however, contain evidentials, which indicate their
sources or types of evidence. See Aikhenvald 2004.)

If after receiving directions from the stranger, you asked another who
was in plain view of the stranger, you would expect the stranger to be
offended. You would be embarrassed if the stranger’s gaze fell upon
you. Corresponding to the authority you ascribe and the trust you
extend to the stranger, you impose a duty on yourself to accept the
testimony, unless you have specific reasons to object. (Contrast the
hearer with the over hearer).

The DR should not be construed as proposing that the hearer
accept the speaker’s testimony without warrant or justification.
Rather, sufficient justification or warrant for acceptance, whether a
priori or a posteriori, is present, factoring in both the background
evidence (1–6) noted above and the constraints that are inherent in the
normal conversational setting. (Exactly how the constraints of the
conversational setting, like the constraint to economize, is to justify
governance by the DR is a difficult one, which cannot be
undertaken here.) On a priori views the DR has a
standing of initial entitlement to acceptance
(section 8.1 below).

Knowledge Norm of Assertion (K-norm): One correctly asserts that
p only if one knows (or represents oneself as knowing) that
p.

On the assumption that speakers generally conform to the K-norm, which
would help explain why the norm continues to hold, hearers will
correspondingly ascribe to speakers knowledge that their assertions
hold. These ascriptions support the DR, since speakers’
knowing is excellent reason to accept their assertions.

According to the K-norm, if you do not know that p, you should not
assert it. A crucial argument for the K-norm is via a version of
Moore’s Paradox, see e.g., Hintikka 1962, Green and
Williams 2007; see also the entry on
epistemic paradoxes,
which treats of related paradoxes, the Preface Paradox, in
particular.

Arguments for the K-norm assume that knowledge is factive,
if S knows that p then p (for difficulties, Hazlett
2010). The K-norm seems to capture the hearer’s point of view: The
hearer accepts the speaker’s testimony without learning of the
speaker’s evidence or reasons or credentials, since the hearer takes
the speaker to know. While cases in which speakers assert without
believing they know is troubling for the K-norm, problems still lurk,
even if speakers assert what they falsely believe they know (see
Williamson 2000, ch.11). (For criticisms of the K-norm that are
related to epistemological issues of testimony discussed below, see
Weiner 2005; Douven 2006; Lackey 2008.)

The K-norm exposes one qualification required for the DR—a
sensitivity to context, in particular, the importance of the testimony.
After a brief look, you assert that the plastic ring I thought I
dropped in your apartment is not there. I respond: “It’s
not plastic, it’s diamond.” Now you would say instead
something like “Well, I guess I’m not sure [or, I
don’t know]. I better check more carefully.” If this
variation in willingness to assert is due to a variation in standards
for knowledge, the DR requires a relativization to contexts.
Epistemic contextualists explain the assertional data as due
to attributions of knowledge of the form “S knows that
p” varying according to context. “Knows”
like “tall” is relative to a standard (comparison class) or
indexical (Lewis 1979/1983, 1996; Unger 1984; Cohen 1988, DeRose 1992, 1995,
2002; see the entry on
epistemic contextualism).

There is another contextual sensitivity that arguably should be
incorporated into the DR. On a Wittgensteinian view,
particularly derived from On Certainty (1969), justification
of belief is ended by ‘groundless’ beliefs.
Anscombe (1981) argues that historical knowledge does not eventuate
in, or only in, the direct testimony of the senses, as proposed by
Hume (1978 [1740], Book I part III section IV). Rather, there will be
certain historical truths (like that Caesar was assassinated) that
serve as a Wittgensteinian ‘hinge’ or groundless
propositions which are “exempt from doubt” (OC 341). They
are to be default-accepted for those who participate in these
historical inquiries, serving to confirm a historical chain’s
accuracy, rather than conversely confirming the historical truth of
the event (Coady 1992; Traiger 1993; Elgin 2010). But they need not be
taken for granted in other contexts of inquiry.

The DR is a step towards introducing a broad epistemic model
which can explain a difference between ultimate or
philosophical justification and conversational
justification. When justification is called for, the infinite
regress argument for justification–ultimate
justification—concludes that no justification chain is ever
complete, since what confers justification must itself be justified
(by a different proposition). Yet, the regress problem does not have a
grip on conversation. Why?

Within conversational justification (e.g., justification to competent
peers), we are called on to justify a belief only through a legitimate
challenge “How do you know that p?” The
presupposition of this question is that the hearer has a specific
reason to challenge the speaker’s assertion or position to know. So a
challenge to an assertion itself carries a burden of legitimation, and
the regress route to skepticism is blocked, if this
default-challenge structure can be defended as epistemic, not
merely practical or pragmatic. The model answers the regress problem
without commitment to the standard alternatives: skepticism,
foundationalism, coherentism (Rorty 1979; Williams 1991; Brandom 1994;
for a view of these restrictions as pragmatic, see Unger 1975; Stroud
1984).

Admittedly, there are numerous circumstances and examples which do not
seem in accord with the DR. The testimony of witnesses in a
law court are not default-accepted by the jury. Given the central
motivation of advertisers to persuade, rather than inform, there is no
default rule for accepting their testimony. You do not default-accept
the stranger’s driving directions to the nearest gas station in a
town, if the stranger tells you it is over 3 hours away. You do not
default-accept testimony when a speaker offers an opinionated
pronouncement e.g., “Raising property taxes is
regressive,” or “Housing prices will fall further next
quarter.” But in these cases, there is a special reason for the
hearer to not accept the speaker’s testimony. They satisfy
the DR’s “unless” clause. With learning,
application of the
DR is fine-tuned, so that further distinctions are drawn
between those who should be default-trusted and those who should not
e.g., the proverbial used car salesmen.

The DR is not the weakest principle that might govern
conversational acceptance. Rather than holding that testimony transmits
warrant or justification or knowledge, a weaker claim is that it yields
to the hearer only some (pro tanto) epistemic reason to
believe the speaker’s assertion (Pritchard 2004; Graham 2006a).
But this weaker version of the DR would yield only
entitlement to qualified, not all-out, acceptance. The result is weaker
than conversational practice reveals.

If testimony does follow the DR, that is a parallel with
immediate perception and memory. But testimony suffers a distinct
vulnerability in our exercise of judgment and free will (Graham 2004).
Testimony, unlike perception and memory, is a product of
communicative intentions that are not lawlike under the relevant
intentional description. Our free will allows for deliberate
deception—lying and other forms of intentional untruthfulness (on
insincerity as distinctive of our functioning as persons, Faulkner
2000). Speakers do not respond mechanically to hearers’ simple
inquiries. They may refuse to answer, and if they answer, they select,
for example, how much detail to provide.

Nevertheless, speakers’ assertions are explained by our viewing them
as rationally motivated without denying free will or
responsibility. The speaker offers an assertion to a hearer with the
(Gricean) presumption that the speaker has an interest in informing
the hearer. On matters where the speaker has nothing to gain, there is
no rational motivation to lie (see further sections
6.4 and 7.1)
Lacking rational motivation, the speaker does not lie. But in telling
the truth, the speaker exercises free will, satisfying a necessary
condition for the ascription of responsibility for the assertion.

If the K-norm is correct and on the assumption above that speakers
generally conform to it, then in normal conditions, a hearer has
sufficient reason to treat the speaker’s assertion as what the speaker
knows. To the challenge to accept ordinary testimony “Why do you
believe that stranger’s testimony?,” a common response is:
“Why shouldn’t I?” That response implies that the burden
is on the challenger to justify any doubts. Hearers so respond
because they recognizes themselves as having good reasons to accept the
speaker’s assertion.

A number of examples, deriving from the ‘Gettier
literature’, raise problems for this and similar
models. Consider a variant of a well known example. Jones asks a
stranger in Manhattan for directions to the Brooklyn Museum, and the
stranger’s answer “Take the #2 to Eastern Parkway.” Jones
picks out the stranger by accident from a group of strangers,
most of whom are not reliable. Does Jones’s luck in picking out a
reliable speaker undermine his coming to know based on the stranger’s
testimony? A reason to answer ‘No’ is that the question is
whether Jones comes to know the directions, not whether the speaker is
reliable. Since the speaker does know the directions, why should Jones
not come to know from the speaker’s testimony? But this is contestable
given the general response to the well-known “Fake Barn”
example. Related problems pull defenders of the transmission model
toward including conditions that hearers’ cognitive faculties are
functioning well to realize the aim of truth in appropriate
environments (Plantinga 1993).

Perhaps, though, the starting assumption that knowledge by the speaker
is necessary for transmission of knowledge to the hearer can be
abandoned. One proposal is that a speaker’s asserting that
p can be sufficient to generate knowledge for a
hearer, in the absence of defeaters, even if the speaker lacks
knowledge (Lackey 1999, 2003, 2008; Graham 2000c; Kusch
2002).

An example in support of this proposal is of a student who would, it
is held, know that p (e.g., that she lives on Elm St.) except
that she suffers skeptical doubts having been swayed by the dreaming
argument. Yet, the student’s assertion as to where she lives is
sufficient for a hearer, who lacks these doubts, to know. Examples
like this are problematic, however, since if the K-norm holds and the
student lacks knowledge, she misrepresents herself, even if
she does transmit knowledge.

Independent of the K-norm, the example implies an instability of
belief, allowing that a counter-argument, which strikes the believer
as unrefutable, is sufficient for belief-undermining-doubts. But do
your students, avowing persuasion in your class by the dreaming
argument, cease believing that they are in your classroom? The student
who appropriately suffers skeptical doubt about her living on Elm
St. manifests no change in behavior, signaling that her current doubts
are transitory. Belief cannot be as subjective or unstable as to allow
for any reasonable doubts to unseat it, e.g., Romeo’s (transitory)
doubts about Juliet’s love for him, occasioned by her going without
him to an office party with eligible bachelors. The unsettling by
epistemic anxiety cannot be sufficient for loss of entitlement to
belief, if belief is to serve in the analysis of knowledge. The point
generalizes. These counterexamples to the knowledge-transmission
thesis are supposed to work, in part, by satisfaction of the other
conditions for knowledge besides belief.
If belief is not merely a psychological condition, whose
contrary is doubt, but has a normative dimension in its role in
knowledge, like entitlement to believe, there will be a close
tie between conditions that undermine the entitlement and conditions
that undermine one’s epistemic position to know. If so, assertion
by the student is justified, and knowledge is transmitted to, not
generated for, the hearer.

These and other difficult cases for the transmission model are offered
on behalf of a rejection of that model. Lackey’s (2008) alternative is
that the words of the speaker, and specifically their reliability, are
the locus of testimonial knowledge, rather than, say, the
speaker’s knowledge.

A very different model for the transmission of testimonial knowledge
draws on Dretske’s information theoretic model of knowledge:

If S’s assertion that p to H carries the information
that p, and H accepts that p on the basis of
S’s testimony, then H knows that p. (Dretske 1981;
Graham 2000a, 2000c)

The carrying of information is a matter of lawlike relations between
a signal and a source. The signal cannot carry the information that
p, unless p, and thus information meets the factivity
implication of knowledge (that if S knows that p then
p).

Like knowledge as well, whether the signal carries the information that
p can depend on what the relevant alternatives are. In
Harman’s (1973) Newspaper Case, a reliable newspaper reports its
knowledge of a certain political event, and the report is accepted by
one of its readers, H. But newspapers other than H’s
reliable, local newspaper erroneously, but sincerely, report
differently. These dissenting reports count as relevant alternatives
to the reader’s belief. The dominant response is that these other
sources bar the transmission of H’s newspaper’s knowledge
to H, since Hcould easily have read one of the other ones, and so the
information would not be transmitted.

Further perplexities for a transmission condition are introduced by an
example of Dretske’s (1982) of a connoisseur, who can well
discern Medoc wines, which he knows to be from Bordeaux. However, he
falsely believes that Chiantis are also from Bordeaux, although he can
readily distinguish a Medoc from a Chianti. He tells a novice truly
that the wine that they are now drinking, which is a Medoc, is a
Bordeaux. Dretske claims that whereas the connoisseur knows that the
wine is from Bordeaux, the novice does not. The connoisseur passes on
his vulnerabilities to the knowledge-seeker, though Dretske concludes
that the connoisseur is himself immunized from them:

You cannot learn that P from someone who tells you that
P if they would say that P whether or not P,
and that holds even if the person happens to know that P.
(Dretske 1982, 110)

Besides appeal to a subjunctive analysis, Dretske’s argument
assumes that the connoisseur’s vulnerabilities undermine only the
novice’s knowing, not his own. If these assumptions are accepted,
the transmission model is in trouble, Dretske concludes, whereas the
prospects for the informational one are brighter, since the
expert’s testimony at best “carries the information that
the wine was a Bordeaux or a Chianti” (Graham 2000a;
Coady 1992, ch. 12, my emphasis).

When hearers are epistemically entitled to accept the speaker’s
assertion, is the entitlement due to testimony itself or instead to
other sources? Is the entitlement conferred a priori or is it
to be justified a posteriori? These questions have been the
center of discussions, though their presuppositions have been
questioned (Kusch 2002, part I; Fricker 2007; Lackey 2008).

The view that our ordinary acceptance of testimony is justified only
a posteriori has been taken as requiring the reductionist
thesis that testimony, unlike perception, is not a fundamental
source of warrant. The acceptance of testimony resides in other
familiar empirical and a posteriori sources, notably
perception, memory, and induction.

The anti-reductionist admits that testimony depends on other sources
like perception, unlike its converse. And the dependence, it is
claimed, is only psychological or causal. But the epistemic warrant or
justification for accepting testimony need not essentially appeal to
these other sources. It may refer only to the speaker’s knowledge,
word-giving (promising), and other principles that are purely
testimonial (Audi 1997; related claims are made by Coady 1992; for
criticisms, Fricker 1995; Graham 2000b).

Strictly, reductionism and anti-reductionism are not incompatible. The
same testimonial transmission can be justified either way, so that
justification can be overdetermined, meeting both inferential and
non-inferential conditions (Graham 2006b). Nevertheless, we will
assume that reductionist and anti-reductionist sources of
justification (warrant, entitlement) are incompatible in cases of
testimonial transmission, which is how they are dialectically
presented.

Hume is taken as the main proponent of reductionism (e.g., Hume
1978 [1740], Bk I part III section IV) due largely to the views he
expresses in “Of Miracles” (1977 [1748]), an essay directed to the
warrant for accepting testimony of miracles (on testimony for the
supernatural, see Coady 1994). Key statements are these:

our assurance in any argument of this kind [from testimony] is
derived from no other principle than our observation of the veracity of
human testimony, and of the usual conformity of facts to the reports of
witnesses. (Hume 1977 [1748], 74)

The reason why we place any credit in witnesses and historians is
not derived from any connexion, which we perceive a
priori, between testimony and reality, but because we are
accustomed to find a conformity between them. (Hume 1977 [1748], 75)

On the usual readings of these passages, each instance of
testimonial transmission is justified only by an implicit record of the
agent’s ratio of past testimonial success, perhaps restricted to
communicational communities of types of testimony and speakers. If so,
a Humean view would be in opposition to the DR (for
discussion of Hume’s views on testimony that are wary of the
usual readings, Traiger 1993; Faulkner 1998; Root 2001; Van Cleve 2006;
Gelfert 2010a). This unadorned empiricist model is the basis for the
standard contrast to a “Reidian” view:

Reid’s position is that any assertion is creditworthy until shown
otherwise; whereas Hume implies that specific evidence for its
reliability is needed. (Stevenson 1993, 433. See also Wolterstorff 2001;
Audi 2006)

The Reidian account of testimonial trust is that since God intended
us to be ‘social creatures’, he implanted in us “a
propensity to speak the truth,” the principle of
veracity, as well as, correspondingly “a disposition to
confide in the veracity of others, and to believe what they tell
us,” the principle of credulity (Reid 1983, 94–95).

The Reid-Hume contrast needs tempering, however, if the usual way to
obtain specific evidence is by checking on the reliability and
sincerity of a speaker, which, as noted earlier, is generally not
feasible. The implication that offering and accepting testimony could
not be a regular habit or practice fuels anti-reductionism.
Reductionism cannot work, it is claimed, because hearers know too
little about speakers and cannot find out more within the testimonial
exchange (Webb 1993; Foley 1994). Hume’s position is
salvageable—his endorsement, noted earlier, of our far-reaching
(epistemic and doxastic) dependence on testimony,
specifically—if there are, and must be, ways to acquire evidence
favoring the acceptance of testimony that do not involve burdensome
checks on the credentials of particular speakers, as with background
evidence. The salvage would neutralize Coady’s observation:

In our ordinary dealings with others we gather information without
this concern for inferring the acceptability of communications from
premises about honesty, reliability, probability, etc. of our
communicants…. (Coady 1992, 143; for similar concerns, Audi
1997)

Schiffer objects that this argument conflates the epistemic and the
psychological:

Whether knowing p is based on knowing q,
isn’t about the actual movement of thought, the considerations
one actually ponders; it’s about the structure of beliefs that
sustain one’s conclusion (2003, 303; Fricker 1995; Burge
1997).

If the automaticity of our response to testimony is not decisive for
whether the epistemic basis is a priori, innate, or empirical,
then, similarly, the evidence of a typical acceptance of testimony is
evidence that our trust in speakers is not ‘blind,’ given
that hearers are responsive to when speakers are unreliable or
insincere.

Another objection to Humean reductionism is that any attempt to justify
testimony through an inductive inference will inevitably be circular.
For the justificatory grounds will almost certainly be obtained, in
part, through testimony (Coady 1992). This criticism assumes that to
justify reliance on testimony overall or in a particular case bars
appeal to evidence of past testimonial success. But it is not evident
that this assumption is correct, or that the restriction would not
equally exclude justification of perception (by its ‘track
record,’ Alston 1993).

Shogenji (2006) responds to this circularity objection and a related
“transcendental” one (a Davidsonian (1984) type argument
that interpretation assumes the general credibility of testimony)
together in two steps. The general credibility of testimony is put
forth as a hypothesis, so that the credibility of testimony is subject
to confirmation or disconfirmation. Our testimonial practice turn out
to be extremely well, albeit tacitly, confirmed, through its
overwhelming success. Confidence in the practice draws epistemically on
this tacit confirmation as part of our inherited and developing
competence in the testimonial practice (Adler 1990, 2002).

Another difficulty alleged against the Humean is that his denial of any
a priori connection “between testimony and
reality” implies that

we might have discovered (though in fact we did not) that there was
no conformity at all between testimony and reality. (Coady 1992, 85)

If Hume does allow for this discovery, it would be difficult to
understand how the practice of testimony persists so robustly, since
the failings would undermine trust. But the result also suggests that
Hume need not allow for the possibility (Schmitt 1994a; Lyons 1997). The
demand to empirically justify reliance on testimony does not entail
that there are not necessary conditions, which must be satisfied for
the practice to be sustained. There is no a priori connection
between private swimming pools and wealth. Yet, a high level of wealth
may be an important necessary condition for the continued construction
of private swimming pools.

Still, if Hume allows for the possibility of a world in which testimony
and reality are discovered not to match, a further, related, difficulty
is held to arise:

whenever they [the ‘Martians’] construct sentences
addressed to each other in the absence (from their vicinity) of the
things designated by the names, but when they are, as we should think,
in a position to report, then they seem to say what we (more
synoptically placed) can observe to be false. But in such a situation
what reason would there be for believing that they even had the
practice of reporting? (Coady 1992, 85)

These objections culminate in an argument that meaning or content, as
well as language learning, are claimed to be impossible absent an a
priori connection of testimony and truth. For if we are constantly
frustrated in checking the truth of our attempts to translate native
utterances, we thereby undermine our claim to understand, or even to
attribute content, to them (Coady 1992; for criticisms Graham
2000b).

The argument is derived from Davidson (1984). He holds that it is a
conceptual truth that we attribute rationality to speakers in
interpreting them, which Davidson understands as implying that the
speaker’s beliefs are predominantly like our own, and, more
disputably, that they are predominantly true.

However, even if these Davidsonian claims hold, there is a barrier to
transferring them to testimony. The vast, shared collection of beliefs
that, in Davidson’s words, are “too dull, trite, or familiar to
stand notice,” (1984, 199) dwarf by comparison the set of
beliefs likely to be expressed in testimony, since the latter are
presented only on the presumption of their informativeness to hearers.
But if testimony is informative, the assertions are among the riskier
constituents of our vast background of ‘dull’ beliefs.
Consequently, they are lesser candidates for Davidson’s a
priori interpretational justification. Among the beliefs a
priori guaranteed of truth by the Davidson-type reasoning would
be ones like that there is an earth, 2+2=4, and bacteria do not study
astro-physics. Except under unusual circumstances, these are not the
kind of beliefs that would be informative to assert (Adler 1994;
Fricker 1995; Elgin 2002; for doubts about a Davidsonian approach,
Ebbs 2002).

This section presented a sketch of reductionism sufficient to
survey some anti-reductionist and a priori criticisms of it.
But we have not provided detailed accounts of either. Although the
background evidence outlined above (section 2)
does not strictly favor
either reductionist or anti-reductionist views, it plays a crucial role
for the reductionist, which is discussed next in section 6.
Section 7
covers a diverse range of anti-reductionist views.

Appeal to the background evidence of the testimonial practice lends
itself to the development of a number of approaches to the a
posteriori justification of testimony with varying implications
for reductionism. The enumerative induction account attributed to
Hume’s ‘On Miracles’ is only one kind of a
posteriori position (Lyons 1997; Rysiew 2000). There is no
assumption that these approaches are exclusive of one another, and in
obvious ways a number of them are complimentary.

The background evidence enumerated above
(section 2) is incorporated into one’s
corpus of beliefs. They constitute a vast source of evidence for us
in regard to the reliability of testimony (but see Pritchard
2004). We acquire knowledge of the trustworthiness of testimony, as
well as knowledge of domains in which the word of others is not to be
default-accepted (e.g., salespeople on the quality of competing
brands).

Along these lines are resources to object to those who have used our
far-reaching dependence on testimony to press that much of our beliefs
rests on a fragile ethical, basis e.g.,

the trustworthiness of members of epistemic communities is the
ultimate foundation for much of our knowledge. (Hardwig 1991, 694; for
developments and criticism see Webb 1993; Govier 1993; Adler
1994; Baier 1994; Holton 1994; Shapin 1994)

In opposition to this fragility claim, we enter testimonial settings
with powerful background beliefs (evidence) to trust the word of the
speaker.

Recent empirical work shows that young children do trust testimony.
However, the trust is selective enough to raise doubts about Reidian
views of children as highly credulous (Harris 2002). In an overview of
current findings, evidence is presented that young children “keep
track of the epistemic reliability of potential informants” and
“monitor the cultural standing of potential informants”
(Harris and Corriveau 2011; extending a theme from Koenig and Harris
2007). Harris and Corriveau (2011) conclude that “taken
together, these two heuristics favour the transmission of information
that is either true or culturally typical.”

Even though the knowledge that subtly guides our patterns of
acceptance of testimony is obtained prior to the testimonial setting,
it is clearly not knowledge a priori—knowledge not
dependent on experience. The appeal to background evidence to justify
our testimonial practice is at variance with the accusation that an
empirical or a posteriori approach demands that “we
remain neutral or skeptical of information unless we have empirical
grounds for thinking it trustworthy…” (Burge 1993,
473).

Elizabeth Fricker (1987, 1994, 1995, 2004, 2006) argues for a
reductionist and internalist justification for particular (local)
testimonial exchanges, in which testimony is taken as inferential or
indirect, in contrast to perception which she takes as providing a
direct justification for corresponding beliefs (see also Sutton
2007). She is skeptical of a global reductionist thesis to
establish the general reliability of testimony. With qualifications,
Fricker denies that we are entitled to default-accept the reliability
of testimony, although she does think a default applies to judging the
sincerity of the speaker. She regards any rule like the DR as
“an epistemic charter for the gullible and
undiscriminating” (1994, 126; but see also, 1995). Fricker claims
that hearers can obtain independent evidence to confirm the belief that
a speaker is trustworthy. She stresses that “insincerity
and honest error are both perfectly possible”:

a hearer should always engage in some assessment of the speaker for
trustworthiness. To believe what is asserted without doing so is to
believe blindly, uncritically. This is gullibility. (145)

Later, explicitly contrasting her view with an analogue of the
DR [the PR thesis], she writes that

My account requires a hearer always to take a critical stance to the
speaker, to assess her for trustworthiness;…on my account, but
not on the PR thesis, the hearer must always be monitoring the speaker
critically. (1994, 154; 1995)

However, if the critical monitoring required is only the
“counterfactual sensitivity” that “if there were any
signs of untrustworthiness, she would pick them up” (1995, 154;
Weiner 2003), so that no special efforts are required of hearers, her
differences with those who uphold the DR or a minimal
anti-reductionist thesis seems to vanish (Goldberg and Henderson 2006).
If, instead, special efforts are required by the hearer, and if our
actual practice is in accord with the DR, it is doubtful
whether her proposal satisfies the claim that checking is infeasible.
This difficulty applies as well to contextualist approaches like that
of Jones (1999) or Kusch (2002).

The role of prior plausibility or epistemic probability at the heart of
a Humean view of testimony can be turned into a Bayesian justification
of testimony (for Bayesian analyses of Hume’s argument in
“On Miracles,” Owen 1987; Sobel 1987). Based on an analysis
of Friedman’s (1987) for legal settings, Goldman (1999, 4.2–4.4)
presents the following model: Given that a witness testifies to a fact
X, what is the probability of X? The answer, given
by Bayes’ Theorem, is that X’s probability is a function of
the likelihood that the witness would so testify, if the
fact X held, and the prior probability of that fact. If the
likelihood of the testimony is greater given X than not, then
testimony raises the probability of X compared to its
original or prior probability. As is typical of Bayesian analyses, a
key question is how individuals are to estimate the various
likelihoods and to secure the prior probabilities (Friedman 1987;
Goldman 1999).

Also along Bayesian lines, Goldman (1999) applies a related theorem of
his and Shaked (Goldman and Shaked 1991) to testimony. The theorem
establishes that under certain conditions (e.g., that there is an
objective likelihood that the witness will testify that p,
if p), one’s posterior degree of belief based on testimony
will reflect an objectively greater nearness to truth than one’s prior
degree of belief.

The Bayesian model provides for a representation of an important
epistemic value of testimony. But its application to the acceptance of
testimony requires an account of the relation of degrees of belief to
full or all-out beliefs, if speakers typically enter unqualified
assertions and hearers typically accept them as stated.

If acceptance of current testimony is based on enumerative induction
over past acceptances, the induction requires verification of the
assertions that hearers accept. These verifications will
themselves appeal to testimony for corroboration. Even if this kind of
circularity is acceptable, as suggested earlier, the correlations alone
do not seem strong enough to justify our conformity to the DR
and to the typical acceptance claim. Further, what will count as
epistemically similar instances of the testimonial setting?
Testimonial settings are diverse in circumstances and speakers.

But instead of relying just on extrapolation from correlations,
inductive inference, including enumerative induction, can take the form
of inference to the best explanation (ibe). (See the
entry on
abduction.)
Ibe is particularly powerful in science as
justifying inferences from observational surprises or puzzles to the
existence of theoretical entities to explain them e.g., to explain why
ice floats on water by appeal to hydrogen bonding (Lipton 2004 on the
difference between inference to the loveliest and inference to
the likeliest hypothesis).

The role of ibe in testimony is straightforward. Normally, if a
stranger responds to your inquiry as to how to get to Harlem by
uttering “Take the uptown #1 to 125th St.,” the
best explanation of why she said that is that she believed it (for good
reason) and that she cared to inform you of it. The inference is
mutually supportive of the counterfactual we assume as hearers:

One wouldn’t have asserted that p unless one believed one
knows p and one wouldn’t have that belief if p
weren’t the case. (Harman 1965; Fricker 1995; Lipton 1998, 2007;
Schiffer 2003; Malmgren 2006)

Obviously, people have false beliefs. Our appeal to the counterfactual
assumes that by-and-large people have true beliefs or at least this is
so for the everyday information that hearers seek from testifiers,
which is easily obtained and readily shared, e.g., local
directions.

If ibe provides sufficient reason to accept the speaker’s
testimony, it may be argued it obviates the need for the DR.
The hearer treats the stranger’s uttering what she did as evidence
of what she believes or what she believes that she knows. The inference
involves no explicitly normative notion, yet it yields the same pattern
of virtually automatic acceptance of testimony in normal settings.

If testimony diminished in reliability—if there were more lies
and errors–the above ibe may still be the best
explanation of why a speaker said what she did: that she believed it
because it is true. If a stranger gives me directions to take the A
subway line downtown, and I recall hearing something to the effect
that there was smoke reported on a subway line in the area, then I
have a specific reason to challenge the stranger. Nevertheless, I am
not thereby in a position to deny that the best explanation of why she
said what she did goes according to the ibe. To accept the
speaker’s testimony, the hearer requires not only that the truth of
the speaker’s testimony provide the best explanation of why she said
what she did, but also that it is good enough.

The representation of Anti-Reductionism so far has been very limited.
Coady’s (1992) critique of reductionism is only one of a number
of forceful anti-reductionist approaches. More recent writings have
taken new turns. Goldberg’s (2007) anti-reductionist leanings,
for example, are one facet of his appeal to testimony for an extended
defense of externalism about content and a reliabilist
epistemology.

In a foundational article, Burge (1993, 1997) offers an a
priori defense of a variant of the DR. His
“Acceptance Principle” is an easily defeasible norm which
only describes our epistemic condition. Its pivotal epistemic term is
entitlement:

A person is entitled to accept as true something that is presented
as true and that is intelligible to him unless there are stronger
reasons not to do so. (1993, 467; Edwards 2000 defends a restatement of
the Acceptance Principle)

The “Acceptance Principle” is comparable to
Davidson’s (1984) “Principle of Charity” and
Grice’s (1989) “Cooperative Principle” in endorsing
the hearer’s default bias to accept the speaker’s
assertions. The hearer does not begin in the neutral position of
treating the speaker’s act of assertion as requiring evaluative
certification as a condition of its acceptance. The entitlement is
conferred by the nature of the testimonial setting. The entitlement
applies independent of whether the hearer has any particular reasons to
trust the speaker.

The argument disassociates the Acceptance Principle from the essential
epistemic dependence on perception or memory. These only serve as
sources to preserve content (Burge 1997, 28; responding to Christensen
and Kornblith 1997). Burge summarizes his main argument as
follows:

We are a priori entitled to accept something that is prima facie
intelligible and presented as true. For prima facie intelligible
propositional contents prima facie presented as true bear an a priori
prima facie conceptual relation to a rational source of true
presentations-as-true: Intelligible propositional expressions
presuppose rational abilities and entitlement; so intelligible
presentations-as-true come prima facie backed by a rational source or
resource of reason; and both the content of intelligible propositional
presentations-as-true and the prima facie rationality of their source
indicate a prima facie source of truth. Intelligible affirmation is the
face of reason; reason is a guide to truth. We are a priori prima facie
entitled to take intelligible affirmation at face value. (Burge 1993,
472–473. For criticism, Audi 2004; Malmgren 2006 offers an extended
critique of Burge, defending a form of ibe)

Burge’s reasoning applies beyond testimony as becomes manifest by
way of the objection that if the intelligibility of the speaker’s
affirmation depends upon the inferential structure of the communication
mechanism, then an impurely preservative mechanism would be required
for understanding, contrary to Burge’s claim of an a priori
entitlement (Bezuidenhout 1998). However, even if the hearer directly
or non-inferentially grasps the speaker’s meaning, the
epistemological question—of what entitles or justifies
belief—remains open. For epistemological purposes, many details of the
actual nature of the communicational mechanism can be abstracted
from.

Burge’s argument reaches beyond testimony. If the intelligibility of
the speaker’s contribution is not dependent on the specifics of the
comprehension process—if the a priori entitlement
resides in the speaker’s reason–then the entitlement is
applicable not only to learning of other’s beliefs (Moran 2005) but
also to acquiring beliefs. But beliefs purport to respond to
reason.

Even if the scope of Burge’s argument goes as far as just
proposed, the entitlement it confers requires “empirical
supplementation” to meet counter-considerations. (Burge 1997, 23)
Without empirical supplementation, normally highly implausible
possibilities of error count as undermining reasons. A stranger
provides me with driving directions. But he speaks with the same accent
as another stranger who recently gave me false directions. Without
bringing in additional empirical information, I am not in a position to
exclude viewing the current informant as suspect because of his
affinities with the previous one. I thereby impugn individuals as
speakers for their membership in a group that share an accent (see
further section 8.1 on “silencing”). The flimsy evidence
is, though, enough to override my entitlement. However, against the
background of common knowledge, this flimsy evidence—the very weak
correlation between accents and reliability or veracity—is easily
outweighed.

Burge’s argument begins with a contrast between justification and
entitlement. Justification calls for the articulation of one’s
reasons. This demanding notion of justification explains why Burge
thinks that the positive-bias or default proposal can be defended only
on a priori grounds. Presumably, Burge takes us not to have
access to background knowledge of empirical reliability, since we can
not generally articulate that knowledge in defense. But must the
reductionist endorse the articulation and accessibility requirement?
The reliability of testimony could be a central, but inaccessible or
not readily accessible, belief that structures how we accept testimony
without representation as a simple propositional belief (but see
Bergmann 2006).

Our cognitive or epistemic activities have (Reidian) presuppositions
not only of trust in perception or memory, but of oneself (Lehrer 1997,
2006). From this presupposition of self-trust a parity or consistency
argument can be developed to trust the word of others (Gibbard 1990;
Foley 1994, 2001). For if we trust our own beliefs, as we do, we ought
to trust the beliefs of others, since we extensively rely on others for
our own opinions and

it is reasonable for me to think that my intellectual faculties and
my intellectual environment are broadly similar to theirs. (Foley 1994,
63)

As stated, this argument contains a posteriori inputs,
specifically in the “similarity” assumption, besides the
safe assumption of our extensive dependence on the testimony of others
for our own opinions.

The parity argument from self-trust also assumes a parallel grounding
for our trust in ourselves and our trust in others. But when I trust my
own beliefs and their sources, my trust is first-personally compelled.
I cannot think “p, but maybe I should not trust myself
or my sources in believing that p.” But there is no such
compulsion from my point of view to regard the beliefs of someone else
as rightly based. I can believe that you believe p, while I do
not.

Proponents of the parity argument could respond by shifting emphasis to
the conditions that verify that I do correctly trust myself,
maintaining that they are just conditions for endorsement of the
outputs of our cognitive mechanisms. The argument would now invoke the
similarity of those mechanisms across the human community to reach its
conclusion. (For critical examination of the parity argument, Schmitt
2002; for further issues of self-trust in relation to testimony, K. Jones
2002.)

The “Assurance View” (Ross 1986; Moran 2005; see also
Hinchman 2005; Faulkner 2007; for objections, see Lackey 2008; Schmitt
2010) claims that a speaker’s assertion is not evidence for what he
believes or the truth of what he asserts. The hearer’s entitlement to
belief resides in the speaker’s standing behind his word, giving his
assurance.

If a speaker’s testimony is evidence of the truth of the belief
expressed by his assertion, then if the hearer could get directly to
that belief, there is no further epistemic force to testimony. On the
Assurance View, there is: The speaker freely takes responsibility for
the truth of his assertion. What is distinctive of testimony on the
Assurance View is that

when the hearer believes the speaker, he not only believes what is
said but does so on the basis of taking the speaker’s word for
it. (Moran 2005, 2)

This normal situation is epistemically different from one in which
the hearer does acquire the intended belief, however

the hearer might not believe the speaker at all, taking him to be a
con man, but yet believe that what he has said is in fact true. (Moran
2005, 2)

Some hold that the requisite assurance is sufficiently binding that the
speaker’s assertion to a hearer, under standard conditions,
amounts to the speaker’s giving his word to the hearer (Thomson
1990; Elgin 2001; for comparisons of promising and asserting, Watson
2004). To trust a speaker is to dismiss (within limits)
counter-evidence to what he asserts. (Welbourne 1979, 1981, 1993). If I
believe that the #2 train stops at Eastern Parkway, but I trust a
stranger who tells me that it does not, then I suspend judgment on my
prior, contrary belief and typically come to his.

The Assurance View draws on Grice’s (1989) distinction between
natural and non-natural meaning. A photograph of a man and a woman
together is evidence for their meeting, regardless of the intentions of
the photographer or the presenter of the photograph. By contrast, a
drawing of the two persons in a similar scene has the non-natural
meaning of their illicit meeting, dependent on the intentions of the
artists. This non-natural meaning is what a speaker’s
communicative intentions confer on his assertion. The speaker cannot
first-personally view his assertion merely as evidence for its truth.
He must take his assertion as up to him (voluntary) and as expressing
his belief, rather than serving as an indicator of the existence of a
state of affairs, which is its truth condition. On the Assurance View,
what gives the speaker’s intention as the reason to believe his
words “independent epistemic value”

can only be…the speaker’s there and then explicitly
presenting his utterance as a reason to believe, with this
presentation being accomplished in the very act of assertion. The
epistemic value of his words is something publicly conferred on them
by the speaker, by presenting his utterance as an assertion…
(Moran 2005, 15)

On the Assurance View, the speaker constitutes his utterance as a
reason for belief, whereas when presenting evidence, its epistemic
import is independent of the presenter.

Because the speaker stands behind his words and invites the
hearer to understand him, the hearer is entitled to hold the speaker to
his words. Someone who overhears a conversation cannot complain should
the speaker’s assertion turn out false (see Hinchman’s 2005
distinction between telling and asserting.) Does—can—this moral
difference make an epistemic difference? The overhearer has no such
social-ethical duty to the speaker, and the speaker feels no ethical
obligation of veracity toward the overhearer. Yet the overhearer has,
it would seem, the same evidence as the hearer.

Drawing on Moran (2005) and related works, anti-reductionists have
emphasized that testimony is second-hand knowledge in the following
way: a hearer can defer to the speaker when the hearer passes on the
speaker’s testimony to another, and the hearer challenges it. For
example, Joe tells Mary that Bill and Jane are divorcing. Mary tells
this to Fred. If Fred questions (challenges) Mary’s testimony,
Mary can defer or deflect Fred’s challenge: “Well,
I’m sorry, but that’s what Joe told me.” Joe will
accept this “buck-passing” as appropriate to his
responsibility. Anti-reductionists take this feature as showing that
the epistemology of testimony is dependent on social relations and the
conferring of epistemic authority on speakers. For if Joe cannot meet
Fred’s challenge to Mary, Mary loses her justification for
asserting that Bill and Jane are divorcing (see Hinchman 2005; Goldberg
2006; McMyler 2007).

Normally, a speaker bears a ‘buck stops here’
responsibility for mistaken testimony. An analogous contrast holds for
arguments. If Alex tells Jane that tonight there will be a snow storm
and Jane passes on to another that school will be closed tomorrow
because the storm will require a snow day, she cannot defer a challenge
to how she knows that the school is closed back to Alex. She can,
of course, defer to Alex for her belief that tomorrow will be a
snow day. But she cannot defer to Alex for herargument that the storm will require a snow day. For she has
accepted Joe’s testimony (or evidence) and made it into her own
reason to draw out the conclusion.

Deferment to the original testifier can then be offered as a problem
for reductionism. Were testimonial transmission inferential, the
deferment to the original speaker is ruled out. Only the hearer who
draws the inference, given the evidence of testimony, is responsible to
meet the challenge. But this conclusion is in conflict with the
permissible ‘buck-passing’ when testimony serves as the
basis for further testimony.

But why does Mary’s deferment to Joe preempt her responsibility?
After all, even though Mary accepts Joe’s word according to
conversational norms, she in turns provides the guarantee or assurance
for the truth of her assertion to Fred. So while Mary rightly defers to
Joe to meet Fred’s challenge (since, specifically, she does not
yet have Joe’s reasons), the deferment cannot eliminate
Mary’s responsibility. Again, this is evident when the hearer
discovers or suspects that the assertion is false.

The Assurance View is only one entrance point for illuminating
overlaps between the ethics and the epistemology of testimony. The
dependence of successful testimonial transfer on the hearer’s
trust is another. Trust implies vulnerability, positive expectations of
good will, and, arguably, empathy (Baier 1994; Jones 1996; Faulkner
2007). These discussions, and in less direct ways those for the
Assurance View, pose a difficult question: How can, or how does, this
vulnerability (to insincerity, specifically), dependence on good will,
and empathy constitute part of the hearer’s reason to accept the
testimony of the speaker?

Hearers’ trust and positive bias toward speakers highlight by
sharp contrast cases in which hearers are guilty of silencing
speakers. Hearers silence speakers when they do not accord them the
standard authority to have their assertions taken as truth-claims
without cause. The topic is explored by Miranda Fricker (2007) as a form of
epistemic injustice. (Pragmatic arguments have been
offered for pornography as silencing women. For different pragmatic
approaches see Langton 1993; McGowan 2003; Saul 2006. For an overview,
Hornsby 2000. For silencing in regard to testimony from memory
(“false memory”), see Campbell 2003.)

According to Fricker, we do someone an epistemic injustice when we do
not accord his or her testimony the level of trust it is due,
especially because of prejudice. One of Fricker’s examples is of
Tom Robinson, the central character in To Kill a Mockingbird,
on trial for his life. Because he is a ‘Negro’ in this
early 20th century viscerally racist southern town, his
honest testimony is rejected, unlike the manifestly not credible
testimony of the prosecution’s local, white witnesses. Fricker
argues that epistemic injustice is rooted in culpable prejudice, given
the evidence available to citizens. Fricker provides other examples,
particularly one from the book and movie “The Talented Mr.
Ripley,” to draw out differences in degrees of culpability.

Silencing in its myriad forms is a serious epistemic injustice.
Silencing of citizens, particularly as members of a minority group,
threatens their autonomy. It threatens pluralist democratic values,
which depend on individuals being afforded opportunities to express and
defend their views in public forums, and to have those views heard
respectfully (Habermas 1996, Rawls 1996).

An informal way to appreciate how serious the injustice is is to think
of how resentful and offended you would be in ordinary gatherings, if
your contribution to the on-going discussion is rudely interrupted or
ignored. The ordinary entitlement to have one’s words heard and
responded to is fundamental to human learning, respect, enjoyment, and
engagement with others.

In legal testimony, worries over a kind of prejudicial, but largely
non-conscious, silencing of a defendant is the ground for a forceful,
and disputed, rule that restricts information (Goldman 1991). Character
evidence about a witness suffers few restrictions. Jurors need to know
how trustworthy and reliable witnesses are. But when it comes to
defendants, courts are circumspect about admitting character evidence.
In civil trials, it is generally inadmissible, and in criminal trials
it is freely introduced only by defendants. Nevertheless, there is
probabilistic relevance. In discussing the legal rules of evidence
(Rule, 404) about character, Walton reports:

Character evidence of this kind [a defendant’s prior assaults
in relation to his current trial], like evidence of previous
convictions, is known to exert such influence on a jury that the
lawyers for both sides will argue strenuously about whether it should
be judged relevant even in the pretrial stages. (2004, 19)

The probative value of character evidence is easily overridden by
its potential influence on the jury (Walton 1997, 20–21). While the exclusion
as a rule depends on practical and legal considerations, there is a
theoretical and empirical justification for it as well. We are subject
to non-conscious prejudices or biases on our judgments of speaker
credibility that we will not recognize, accept, or endorse.
(Non-conscious prejudices or biases are the subject of extensive
research. See, for example, Wilson 2002; Gendler 2008.)

How should silencing due to prejudice, as a form of testimonial
injustice, be conceptualized for epistemological purposes? What lessons
should be learned? Prejudice resists modification with available,
clear, contrary information or evidence.

Fricker (2007) develops a virtue epistemic perspective on the
model of Aristotelian virtue ethics (Zagzebski 1996). The epistemically
virtuous agent perceives or discerns which speakers are credible
typically without special effort. The agent overcomes prejudices, being
motivated to judge correctly by an interest in good information.
(There are complexities of Fricker’s account: she is a
contextualist about testimonial justice, she takes the moral perception
of the virtuous agent to be theory-laden, and she views the virtue of
testimonial justice to be both intellectual and ethical—a hybrid
virtue that aims at once at truth and justice.)

However, does epistemic virtue theory provide the best model for the
ordinary epistemic agent in conversational exchanges across a
variety of inquiries? One contrast is with Peircean models of
inquiry. The Peircean model requires that participation in inquiry be
open, among other conditions (e.g., competition). In the ideal case, there
are internal incentives against silencing; modest prejudices or biases
tend to cancel out. Self-correction replaces strong demands for the
development of virtuous character traits (beyond some minimum). Not
only is there less of a burden on participation than on Aristotelian
approaches, but individual differences in these traits, like a tendency
to be dogmatic, will likely be better at preserving a diversity of
ideas, particularly minority or disfavored ideas (Mill 1978 [1859]; for
development, Kitcher 2001; Sunstein 2003. On good biases, Antony
1993).

Reductionists are held to be in the grip of an individualism which
maintains that testimony is an inferior source of knowledge because the
hearer believes the speaker’s assertion without the
hearer’s own autonomous judgment of its truth. Clearly, knowledge
that derives purely from testimony cannot meet the (Platonic)
requirement that a person knows that p only if that person can
explain why p is the case. I can know from testimony that Bill
despises Jim without knowing why Bill despises Jim. My knowledge that
Bill despises Jim will then not be as stable. But if I have an
explanation of why Bill despises Jim, because, say, of Jim’s role
in denying Bill tenure, I will be suspicious of testimony that Bill and
Jim are very friendly.

Critics of reductionism identify it with an individualistic
epistemology for maintaining that testimonial knowledge depends
epistemically only upon non-social sources, rather than being an
autonomous epistemic source of knowledge. Were reductionism to restrict
basic sources for testimonial inference and transition to only
non-social sources, reductionists would fail a ‘litmus’
test for an adequate epistemology (Schmitt 1994a, 4).

The alleged neglect of testimony in epistemology generally has been
taken as the result of the dominant influence of epistemologies that
are not just individualistic, which neglect ethical and social
dimensions of inquiry like trust (Hardwig 1985, 1991; Welbourne 1981,
1993; Schmitt 1987, 1994a; Baier 1993; Webb 1993; Goldman 1999;
K. Jones 1999, 2002; Fricker 2006; Faulkner 2000; Kusch 2002. For
Kant’s contribution, Gelfert 2006, 2010b; see the entry on
social epistemology). One hypothesis to explain the
neglect within the main epistemological traditions is just that
testimony will at best transmit knowledge, rather than playing a role
in its discovery or generation, a hypothesis denied by
anti-reductionists and others (Lipton 1998; Kusch 2002; Lackey
2008).

A strong view among social epistemologists is that an individual cannot
be said to know, via testimony, that p, unless p is
known in the community (Welbourne 1993; Brandom 1994; Faulkner 2002).
In contrast, an apparent individualist tradition broached in
Plato’s Theaetetus is that the ideal for knowledge is
that of the autonomous knower judging the truth for himself without
dependence on others. The dependence on others, unlike the dependence
on perception, filters one’s information through another
interpretive mind with its own biases and fallibility.

In a section of the Theaetetus arguing that true
judgment and knowledge are different, Socrates hypothesizes that

a jury has been justly persuaded of some matter which only an
eye-witness could know, and which cannot otherwise be known; suppose
they come to their decision upon hearsay, forming a true judgment: then
they have decided the case without knowledge, but, granted they did
their job well, being correctly persuaded? (Plato 1992, 201b–c)

More pointedly,
Locke:

we may as rationally hope to see with other men’s eyes as to know by
other men’s understanding…The floating of other men’s opinions
in our brains makes us not one jot the more knowing, though they
happen to be true. What in them was science is in us but
opiniatrety. (Locke 1961 [1689], 58)

Although these quotes capture the worry of something epistemically
inferior about learning of an event second-hand, the epistemologies
that Plato and Locke are working with do not align with contemporary
views, e.g., assuming that the hearer is more epistemically high-minded
than the casual speaker in the contrast of belief (or opinion) and
knowledge. In the Theaetetus there are suggestions that the
testifiers are “orators and lawyers” who are skilled at
persuasion, rather than ordinary cases of transmitting information by a
stranger like the Meno, a case of a guide telling you the road to
Larissa (Plato 2002, 97a–c). The passage from the Theaetetus
also involves tight time demands in informing others about complex
matters (201a–b). Similarly, there are passages that indicate that
Locke’s disfavor with the value of testimony was limited to
judgements outside secure and pedestrian domains (e.g., Locke 1961 [1689], Bk
4 ch.16 sec8–9). For Kant, moral principles are not properly learned
through testimony, thereby reconciling Kant’s view of learning
from testimony with his demand that moral principles be autonomously
endorsed (Gelfert 2006). (For historical background on testimony
generally, Coady 1992, part II; Kennedy 2004.)

An epistemic agent whose beliefs do not depend upon testimonial
transmission knows very little. The individualism-autonomy ideal only
appears plausible if we ignore our limitations and our need to
economize. If we do not ignore these, autonomy will appear irrational
for accepting a huge loss of information, ignoring how we exploit
a division of epistemic labor (Putnam 1975; Kitcher 1993). We
usefully divide roles in the kind of information we acquire and so can
transmit, e.g., about world events, the weather, sports scores, which
no one, nor any small group of us, could achieve on his or her
own. Our reliance on the division of epistemic labor extends not just
to the pronouncements of others better positioned, but to their
reasons or evidence. Owens (2000) offers the provocative thesis that
when a speaker transmits the knowledge that p to a hearer,
the hearer may be held to have borrowed the speaker’s reasons
for p, without necessarily knowing their content.

The worries over autonomy are forceful in cases in which there is
reason not to fully trust the judgments of others. In a wide range of
ordinary cases, however, it is evident that others, either singly or as
a group, are bound to be more reliable than oneself and to report
accurately. Consequently, it would be self-defeating to ignore, or to
unfeasibly try to regularly check upon, their transmissions.